LF: Re: DBF39 in VK

Andre' Kesteloot akestelo@bellatlantic.net
Mon, 25 Jan 1999 19:49:02 -0500

let us think about the VK calculatiosn re-our own operations

Steve Olney wrote:

> > Hello,
> > Steve's graph of the station on 138.830 is very interesting. If a signal
> > such as this 60 kW (some say 100 kW) can be pulled out of the noise by
> > integrating the signal over 30 minutes, maybe we need to ask Europes
> > strongest station (G3LDO?) to use vscw (=very slow cw) and use dot length
> > of hours or even a dot length on one day .... just a thought ...
> I have been thinking about this for a while now.  Assuming 100kW and an
> EIRP of say 80kW for DBF39 and best EIRPs of about 1W for an amateur setup,
> we are almost 50dB down.  The display S/N of DBF39 is about +10 S/N for a
> 30 minute record.  I need at least a +3dB display S/N to make a positive
> identification.  That leaves us with a deficit of 43dB.  If you look at the
> new images I have put up on my Web Page you can see that the DBF39 is
> spread over about 80 FFT bins.  If you could contain the amateur signal in
> one FFT bin (0.009ppm - need to be locked to one of the time and frequency
> station signals at both ends) you would get a 19dB improvement.  That
> leaves us with a 24dB deficit.  If we integrate over about 2 hours (the
> current dark path window to VK from UK) we gain another 6dB.  Still 18dB
> down. Doesn't look promising.
> On a more optimistic note the records I have taken are only a small sample
> (2 runs) and it is possible that some form of enhancement may exist (SIDs)
> which could get us over the line.  Also the records here are taken over the
> western path from here which is mostly over land.  At other times of the
> year a dark path may be possible to the east of the Pacific/Atlantic which
> should be better.  ZL is better placed now as they have a dark path over
> Pacific/Atlantic.
> The new images (DBF39? and DCF49?) are found by taking the "Other LF signal
> sources" link from
> http://www.zeta.org.au/~ollaneg/lowfer.htm
> 73s Steve Olney (VK2ZTO)
> ========================================
> email:  ollaneg@zeta.org.au
> Web Page:  http://www.zeta.org.au/~ollaneg
> LowFer: http://www.zeta.org.au/~ollaneg/lowfer.htm
> LF Receiving - FRG-100, 8-turn 10sqm Loop
> or Ferrite Loop + K0LR Preamp
> ========================================